1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a flash memory device by performing a nitrogen atom-introducing treatment to improve the data retention reliability of the flash memory device.
2. Description of the Prior Art
Flash memory devices are capable of writing, rewriting, and electrically erasing data in memory cells. In addition, data stored in the flash memory device persists even when power is turned off. This persistent characteristic makes the flash memory devices useful for data storage in applications such as mobile phones, digital cameras, video players, or personal digital assistants (PDA).
Please refer to FIG. 1. FIG. 1 is a schematic cross-sectional view illustrating a flash memory device in the prior art. As shown in FIG. 1, the flash memory device in the prior art includes a stacked gate structure 100 disposed on a substrate 100. The stacked gate structure 10 sequentially includes a tunnel dielectric layer 102, a floating gate 104, an inter-gate dielectric layer 106, and a control gate 108. In addition, in order to enhance the data retention reliability of the flash memory device, the flash memory device usually further includes a linear oxide layer 110 and a nitride spacer 112.
However, the higher the memory capacity is, the higher the integration degree of the flash memory devices should be, such that the thickness of the linear oxide layer 110 and the thickness of the nitride spacer 112 are unavoidably limited. As the feature size of the flash memory device decreases, the flash memory device becomes weaker in the important characteristics, such as high temperature operating life (HTOL). Therefore, the method of manufacturing the flash memory device requires improvement to enhance the integration degree and the data retention reliability at the same time.